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phab/src/applications/differential/parser/DifferentialHunkParser.php
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DifferentialHunkParser.php
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<?php
final class DifferentialHunkParser extends Phobject {
private $oldLines;
private $newLines;
private $intraLineDiffs;
private $depthOnlyLines;
private $visibleLinesMask;
private $normalized;
/**
* Get a map of lines on which hunks start, other than line 1. This
* datastructure is used to determine when to render "Context not available."
* in diffs with multiple hunks.
*
* @return dict<int, bool> Map of lines where hunks start, other than line 1.
*/
public function getHunkStartLines(array $hunks) {
assert_instances_of($hunks, 'DifferentialHunk');
$map = array();
foreach ($hunks as $hunk) {
$line = $hunk->getOldOffset();
if ($line > 1) {
$map[$line] = true;
}
}
return $map;
}
private function setVisibleLinesMask($mask) {
$this->visibleLinesMask = $mask;
return $this;
}
public function getVisibleLinesMask() {
if ($this->visibleLinesMask === null) {
throw new PhutilInvalidStateException('generateVisibileLinesMask');
}
return $this->visibleLinesMask;
}
private function setIntraLineDiffs($intra_line_diffs) {
$this->intraLineDiffs = $intra_line_diffs;
return $this;
}
public function getIntraLineDiffs() {
if ($this->intraLineDiffs === null) {
throw new PhutilInvalidStateException('generateIntraLineDiffs');
}
return $this->intraLineDiffs;
}
private function setNewLines($new_lines) {
$this->newLines = $new_lines;
return $this;
}
public function getNewLines() {
if ($this->newLines === null) {
throw new PhutilInvalidStateException('parseHunksForLineData');
}
return $this->newLines;
}
private function setOldLines($old_lines) {
$this->oldLines = $old_lines;
return $this;
}
public function getOldLines() {
if ($this->oldLines === null) {
throw new PhutilInvalidStateException('parseHunksForLineData');
}
return $this->oldLines;
}
public function getOldLineTypeMap() {
$map = array();
$old = $this->getOldLines();
foreach ($old as $o) {
if (!$o) {
continue;
}
$map[$o['line']] = $o['type'];
}
return $map;
}
public function setOldLineTypeMap(array $map) {
$lines = $this->getOldLines();
foreach ($lines as $key => $data) {
$lines[$key]['type'] = idx($map, $data['line']);
}
$this->oldLines = $lines;
return $this;
}
public function getNewLineTypeMap() {
$map = array();
$new = $this->getNewLines();
foreach ($new as $n) {
if (!$n) {
continue;
}
$map[$n['line']] = $n['type'];
}
return $map;
}
public function setNewLineTypeMap(array $map) {
$lines = $this->getNewLines();
foreach ($lines as $key => $data) {
$lines[$key]['type'] = idx($map, $data['line']);
}
$this->newLines = $lines;
return $this;
}
public function setDepthOnlyLines(array $map) {
$this->depthOnlyLines = $map;
return $this;
}
public function getDepthOnlyLines() {
return $this->depthOnlyLines;
}
public function setNormalized($normalized) {
$this->normalized = $normalized;
return $this;
}
public function getNormalized() {
return $this->normalized;
}
public function getIsDeleted() {
foreach ($this->getNewLines() as $line) {
if ($line) {
// At least one new line, so the entire file wasn't deleted.
return false;
}
}
foreach ($this->getOldLines() as $line) {
if ($line) {
// No new lines, at least one old line; the entire file was deleted.
return true;
}
}
// This is an empty file.
return false;
}
/**
* Returns true if the hunks change anything, including whitespace.
*/
public function getHasAnyChanges() {
return $this->getHasChanges('any');
}
private function getHasChanges($filter) {
if ($filter !== 'any' && $filter !== 'text') {
throw new Exception(pht("Unknown change filter '%s'.", $filter));
}
$old = $this->getOldLines();
$new = $this->getNewLines();
$is_any = ($filter === 'any');
foreach ($old as $key => $o) {
$n = $new[$key];
if ($o === null || $n === null) {
// One side is missing, and it's impossible for both sides to be null,
// so the other side must have something, and thus the two sides are
// different and the file has been changed under any type of filter.
return true;
}
if ($o['type'] !== $n['type']) {
return true;
}
if ($o['text'] !== $n['text']) {
if ($is_any) {
// The text is different, so there's a change.
return true;
} else if (trim($o['text']) !== trim($n['text'])) {
return true;
}
}
}
// No changes anywhere in the file.
return false;
}
/**
* This function takes advantage of the parsing work done in
* @{method:parseHunksForLineData} and continues the struggle to hammer this
* data into something we can display to a user.
*
* In particular, this function re-parses the hunks to make them equivalent
* in length for easy rendering, adding `null` as necessary to pad the
* length.
*
* Anyhoo, this function is not particularly well-named but I try.
*
* NOTE: this function must be called after
* @{method:parseHunksForLineData}.
*/
public function reparseHunksForSpecialAttributes() {
$rebuild_old = array();
$rebuild_new = array();
$old_lines = array_reverse($this->getOldLines());
$new_lines = array_reverse($this->getNewLines());
while (count($old_lines) || count($new_lines)) {
$old_line_data = array_pop($old_lines);
$new_line_data = array_pop($new_lines);
if ($old_line_data) {
$o_type = $old_line_data['type'];
} else {
$o_type = null;
}
if ($new_line_data) {
$n_type = $new_line_data['type'];
} else {
$n_type = null;
}
// This line does not exist in the new file.
if (($o_type != null) && ($n_type == null)) {
$rebuild_old[] = $old_line_data;
$rebuild_new[] = null;
if ($new_line_data) {
array_push($new_lines, $new_line_data);
}
continue;
}
// This line does not exist in the old file.
if (($n_type != null) && ($o_type == null)) {
$rebuild_old[] = null;
$rebuild_new[] = $new_line_data;
if ($old_line_data) {
array_push($old_lines, $old_line_data);
}
continue;
}
$rebuild_old[] = $old_line_data;
$rebuild_new[] = $new_line_data;
}
$this->setOldLines($rebuild_old);
$this->setNewLines($rebuild_new);
$this->updateChangeTypesForNormalization();
return $this;
}
public function generateIntraLineDiffs() {
$old = $this->getOldLines();
$new = $this->getNewLines();
$diffs = array();
$depth_only = array();
foreach ($old as $key => $o) {
$n = $new[$key];
if (!$o || !$n) {
continue;
}
if ($o['type'] != $n['type']) {
$o_segments = array();
$n_segments = array();
$tab_width = 2;
$o_text = $o['text'];
$n_text = $n['text'];
if ($o_text !== $n_text && (ltrim($o_text) === ltrim($n_text))) {
$o_depth = $this->getIndentDepth($o_text, $tab_width);
$n_depth = $this->getIndentDepth($n_text, $tab_width);
if ($o_depth < $n_depth) {
$segment_type = '>';
$segment_width = $this->getCharacterCountForVisualWhitespace(
$n_text,
($n_depth - $o_depth),
$tab_width);
if ($segment_width) {
$n_text = substr($n_text, $segment_width);
$n_segments[] = array(
$segment_type,
$segment_width,
);
}
} else if ($o_depth > $n_depth) {
$segment_type = '<';
$segment_width = $this->getCharacterCountForVisualWhitespace(
$o_text,
($o_depth - $n_depth),
$tab_width);
if ($segment_width) {
$o_text = substr($o_text, $segment_width);
$o_segments[] = array(
$segment_type,
$segment_width,
);
}
}
// If there are no remaining changes to this line after we've marked
// off the indent depth changes, this line was only modified by
// changing the indent depth. Mark it for later so we can change how
// it is displayed.
if ($o_text === $n_text) {
$depth_only[$key] = $segment_type;
}
}
$intraline_segments = ArcanistDiffUtils::generateIntralineDiff(
$o_text,
$n_text);
foreach ($intraline_segments[0] as $o_segment) {
$o_segments[] = $o_segment;
}
foreach ($intraline_segments[1] as $n_segment) {
$n_segments[] = $n_segment;
}
$diffs[$key] = array(
$o_segments,
$n_segments,
);
}
}
$this->setIntraLineDiffs($diffs);
$this->setDepthOnlyLines($depth_only);
return $this;
}
public function generateVisibileLinesMask($lines_context) {
$old = $this->getOldLines();
$new = $this->getNewLines();
$max_length = max(count($old), count($new));
$visible = false;
$last = 0;
$mask = array();
for ($cursor = -$lines_context; $cursor < $max_length; $cursor++) {
$offset = $cursor + $lines_context;
if ((isset($old[$offset]) && $old[$offset]['type']) ||
(isset($new[$offset]) && $new[$offset]['type'])) {
$visible = true;
$last = $offset;
} else if ($cursor > $last + $lines_context) {
$visible = false;
}
if ($visible && $cursor > 0) {
$mask[$cursor] = 1;
}
}
$this->setVisibleLinesMask($mask);
return $this;
}
public function getOldCorpus() {
return $this->getCorpus($this->getOldLines());
}
public function getNewCorpus() {
return $this->getCorpus($this->getNewLines());
}
private function getCorpus(array $lines) {
$corpus = array();
foreach ($lines as $l) {
if ($l['type'] != '\\') {
if ($l['text'] === null) {
// There's no text on this side of the diff, but insert a placeholder
// newline so the highlighted line numbers match up.
$corpus[] = "\n";
} else {
$corpus[] = $l['text'];
}
}
}
return $corpus;
}
public function parseHunksForLineData(array $hunks) {
assert_instances_of($hunks, 'DifferentialHunk');
$old_lines = array();
$new_lines = array();
foreach ($hunks as $hunk) {
$lines = $hunk->getSplitLines();
$line_type_map = array();
$line_text = array();
foreach ($lines as $line_index => $line) {
if (isset($line[0])) {
$char = $line[0];
switch ($char) {
case ' ':
$line_type_map[$line_index] = null;
$line_text[$line_index] = substr($line, 1);
break;
case "\r":
case "\n":
// NOTE: Normally, the first character is a space, plus, minus or
// backslash, but it may be a newline if it used to be a space and
// trailing whitespace has been stripped via email transmission or
// some similar mechanism. In these cases, we essentially pretend
// the missing space is still there.
$line_type_map[$line_index] = null;
$line_text[$line_index] = $line;
break;
case '+':
case '-':
case '\\':
$line_type_map[$line_index] = $char;
$line_text[$line_index] = substr($line, 1);
break;
default:
throw new Exception(
pht(
'Unexpected leading character "%s" at line index %s!',
$char,
$line_index));
}
} else {
$line_type_map[$line_index] = null;
$line_text[$line_index] = '';
}
}
$old_line = $hunk->getOldOffset();
$new_line = $hunk->getNewOffset();
$num_lines = count($lines);
for ($cursor = 0; $cursor < $num_lines; $cursor++) {
$type = $line_type_map[$cursor];
$data = array(
'type' => $type,
'text' => $line_text[$cursor],
'line' => $new_line,
);
if ($type == '\\') {
$type = $line_type_map[$cursor - 1];
$data['text'] = ltrim($data['text']);
}
switch ($type) {
case '+':
$new_lines[] = $data;
++$new_line;
break;
case '-':
$data['line'] = $old_line;
$old_lines[] = $data;
++$old_line;
break;
default:
$new_lines[] = $data;
$data['line'] = $old_line;
$old_lines[] = $data;
++$new_line;
++$old_line;
break;
}
}
}
$this->setOldLines($old_lines);
$this->setNewLines($new_lines);
return $this;
}
public function parseHunksForHighlightMasks(
array $changeset_hunks,
array $old_hunks,
array $new_hunks) {
assert_instances_of($changeset_hunks, 'DifferentialHunk');
assert_instances_of($old_hunks, 'DifferentialHunk');
assert_instances_of($new_hunks, 'DifferentialHunk');
// Put changes side by side.
$olds = array();
$news = array();
$olds_cursor = -1;
$news_cursor = -1;
foreach ($changeset_hunks as $hunk) {
$n_old = $hunk->getOldOffset();
$n_new = $hunk->getNewOffset();
$changes = $hunk->getSplitLines();
foreach ($changes as $line) {
$diff_type = $line[0]; // Change type in diff of diffs.
$orig_type = $line[1]; // Change type in the original diff.
if ($diff_type == ' ') {
// Use the same key for lines that are next to each other.
if ($olds_cursor > $news_cursor) {
$key = $olds_cursor + 1;
} else {
$key = $news_cursor + 1;
}
$olds[$key] = null;
$news[$key] = null;
$olds_cursor = $key;
$news_cursor = $key;
} else if ($diff_type == '-') {
$olds[] = array($n_old, $orig_type);
$olds_cursor++;
} else if ($diff_type == '+') {
$news[] = array($n_new, $orig_type);
$news_cursor++;
}
if (($diff_type == '-' || $diff_type == ' ') && $orig_type != '-') {
$n_old++;
}
if (($diff_type == '+' || $diff_type == ' ') && $orig_type != '-') {
$n_new++;
}
}
}
$offsets_old = $this->computeOffsets($old_hunks);
$offsets_new = $this->computeOffsets($new_hunks);
// Highlight lines that were added on each side or removed on the other
// side.
$highlight_old = array();
$highlight_new = array();
$last = max(last_key($olds), last_key($news));
for ($i = 0; $i <= $last; $i++) {
if (isset($olds[$i])) {
list($n, $type) = $olds[$i];
if ($type == '+' ||
($type == ' ' && isset($news[$i]) && $news[$i][1] != ' ')) {
$highlight_old[] = $offsets_old[$n];
}
}
if (isset($news[$i])) {
list($n, $type) = $news[$i];
if ($type == '+' ||
($type == ' ' && isset($olds[$i]) && $olds[$i][1] != ' ')) {
$highlight_new[] = $offsets_new[$n];
}
}
}
return array($highlight_old, $highlight_new);
}
public function makeContextDiff(
array $hunks,
$is_new,
$line_number,
$line_length,
$add_context) {
assert_instances_of($hunks, 'DifferentialHunk');
$context = array();
if ($is_new) {
$prefix = '+';
} else {
$prefix = '-';
}
foreach ($hunks as $hunk) {
if ($is_new) {
$offset = $hunk->getNewOffset();
$length = $hunk->getNewLen();
} else {
$offset = $hunk->getOldOffset();
$length = $hunk->getOldLen();
}
$start = $line_number - $offset;
$end = $start + $line_length;
// We need to go in if $start == $length, because the last line
// might be a "\No newline at end of file" marker, which we want
// to show if the additional context is > 0.
if ($start <= $length && $end >= 0) {
$start = $start - $add_context;
$end = $end + $add_context;
$hunk_content = array();
$hunk_pos = array('-' => 0, '+' => 0);
$hunk_offset = array('-' => null, '+' => null);
$hunk_last = array('-' => null, '+' => null);
foreach (explode("\n", $hunk->getChanges()) as $line) {
$in_common = strncmp($line, ' ', 1) === 0;
$in_old = strncmp($line, '-', 1) === 0 || $in_common;
$in_new = strncmp($line, '+', 1) === 0 || $in_common;
$in_selected = strncmp($line, $prefix, 1) === 0;
$skip = !$in_selected && !$in_common;
if ($hunk_pos[$prefix] <= $end) {
if ($start <= $hunk_pos[$prefix]) {
if (!$skip || ($hunk_pos[$prefix] != $start &&
$hunk_pos[$prefix] != $end)) {
if ($in_old) {
if ($hunk_offset['-'] === null) {
$hunk_offset['-'] = $hunk_pos['-'];
}
$hunk_last['-'] = $hunk_pos['-'];
}
if ($in_new) {
if ($hunk_offset['+'] === null) {
$hunk_offset['+'] = $hunk_pos['+'];
}
$hunk_last['+'] = $hunk_pos['+'];
}
$hunk_content[] = $line;
}
}
if ($in_old) { ++$hunk_pos['-']; }
if ($in_new) { ++$hunk_pos['+']; }
}
}
if ($hunk_offset['-'] !== null || $hunk_offset['+'] !== null) {
$header = '@@';
if ($hunk_offset['-'] !== null) {
$header .= ' -'.($hunk->getOldOffset() + $hunk_offset['-']).
','.($hunk_last['-'] - $hunk_offset['-'] + 1);
}
if ($hunk_offset['+'] !== null) {
$header .= ' +'.($hunk->getNewOffset() + $hunk_offset['+']).
','.($hunk_last['+'] - $hunk_offset['+'] + 1);
}
$header .= ' @@';
$context[] = $header;
$context[] = implode("\n", $hunk_content);
}
}
}
return implode("\n", $context);
}
private function computeOffsets(array $hunks) {
assert_instances_of($hunks, 'DifferentialHunk');
$offsets = array();
$n = 1;
foreach ($hunks as $hunk) {
$new_length = $hunk->getNewLen();
$new_offset = $hunk->getNewOffset();
for ($i = 0; $i < $new_length; $i++) {
$offsets[$n] = $new_offset + $i;
$n++;
}
}
return $offsets;
}
private function getIndentDepth($text, $tab_width) {
$len = strlen($text);
$depth = 0;
for ($ii = 0; $ii < $len; $ii++) {
$c = $text[$ii];
// If this is a space, increase the indent depth by 1.
if ($c == ' ') {
$depth++;
continue;
}
// If this is a tab, increase the indent depth to the next tabstop.
// For example, if the tab width is 4, these sequences both lead us to
// a visual width of 8, i.e. the cursor will be in the 8th column:
//
// <tab><tab>
// <space><tab><space><space><space><tab>
if ($c == "\t") {
$depth = ($depth + $tab_width);
$depth = $depth - ($depth % $tab_width);
continue;
}
break;
}
return $depth;
}
private function getCharacterCountForVisualWhitespace(
$text,
$depth,
$tab_width) {
// Here, we know the visual indent depth of a line has been increased by
// some amount (for example, 6 characters).
// We want to find the largest whitespace prefix of the string we can
// which still fits into that amount of visual space.
// In most cases, this is very easy. For example, if the string has been
// indented by two characters and the string begins with two spaces, that's
// a perfect match.
// However, if the string has been indented by 7 characters, the tab width
// is 8, and the string begins with "<space><space><tab>", we can only
// mark the two spaces as an indent change. These cases are unusual.
$character_depth = 0;
$visual_depth = 0;
$len = strlen($text);
for ($ii = 0; $ii < $len; $ii++) {
if ($visual_depth >= $depth) {
break;
}
$c = $text[$ii];
if ($c == ' ') {
$character_depth++;
$visual_depth++;
continue;
}
if ($c == "\t") {
// Figure out how many visual spaces we have until the next tabstop.
$tab_visual = ($visual_depth + $tab_width);
$tab_visual = $tab_visual - ($tab_visual % $tab_width);
$tab_visual = ($tab_visual - $visual_depth);
// If this tab would take us over the limit, we're all done.
$remaining_depth = ($depth - $visual_depth);
if ($remaining_depth < $tab_visual) {
break;
}
$character_depth++;
$visual_depth += $tab_visual;
continue;
}
break;
}
return $character_depth;
}
private function updateChangeTypesForNormalization() {
if (!$this->getNormalized()) {
return;
}
// If we've parsed based on a normalized diff alignment, we may currently
// believe some lines are unchanged when they have actually changed. This
// happens when:
//
// - a line changes;
// - the change is a kind of change we normalize away when aligning the
// diff, like an indentation change;
// - we normalize the change away to align the diff; and so
// - the old and new copies of the line are now aligned in the new
// normalized diff.
//
// Then we end up with an alignment where the two lines that differ only
// in some some trivial way are aligned. This is great, and exactly what
// we're trying to accomplish by doing all this alignment stuff in the
// first place.
//
// However, in this case the correctly-aligned lines will be incorrectly
// marked as unchanged because the diff alorithm was fed normalized copies
// of the lines, and these copies truly weren't any different.
//
// When lines are aligned and marked identical, but they're not actually
// identcal, we now mark them as changed. The rest of the processing will
// figure out how to render them appropritely.
$new = $this->getNewLines();
$old = $this->getOldLines();
foreach ($old as $key => $o) {
$n = $new[$key];
if (!$o || !$n) {
continue;
}
if ($o['type'] === null && $n['type'] === null) {
if ($o['text'] !== $n['text']) {
$old[$key]['type'] = '-';
$new[$key]['type'] = '+';
}
}
}
$this->setOldLines($old);
$this->setNewLines($new);
}
}
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